The present invention relates to a sound signal outputting device, a sound signal outputting method, and a computer-readable recording medium.
Various speaker units capable of producing a surround-sound feeling by attaching a different characteristic to sounds output from a plurality of speaker units respectively have been proposed. For example, in the array speaker unit set forth in JP-A-2006-238155, an array speaker for outputting high-frequency sounds and woofers for outputting low-frequency sounds are provided. The signals on respective channels being input into the array speaker unit are separated into the low-frequency sounds and the high-frequency sounds. The low-frequency sounds are output from the woofers. In contrast, the high-frequency sounds are supplied from the array speakers. At that time, a different delay is attached every speaker unit constituting the array speaker. The high-frequency sounds output from respective speaker units interfere mutually in a space, and as a result the sound beam is produced toward a predetermined direction. Such sound beam is produced on respective channels. Respective sound beams arrive at the listener after they are reflected from the wall surface, and the like of the room. Consequently, the surround-sound feeling can be caused in the listener as if the speakers are arranged at plural locations of the room.
In the technology set forth in JP-A-2006-238155, the direction control of the sound beam (referred to as the “directivity control” hereinafter) is applied by controlling delay times of the sounds being output from respective speaker units. However, constraint based upon the principle is imposed upon the directivity control. That is, in order to control the low-frequency sounds (long wavelength), the array whose width is very wide is needed and inevitably an enclosure of the array speaker unit must be extended in length. Also, in order to control the high-frequency sounds (short wavelength), the speaker units of small diameter must be aligned at a narrow pitch. However, a width of the enclosure cannot be ensured without limitation for the reason of design of the speaker unit, so that the speaker units of small diameter cannot have an enough low-frequency reproducing performance.
In view of the above limitation, in the array speaker unit set forth in JP-A-2006-238155, both the “surround-sound feeling” and the “low-frequency reproduction” are implemented by classifying the frequency components into a low-frequency band and a high-frequency band such that the directivity control is applied only to the high-frequency band and the low-frequency component is reproduced by the woofers. However, according to such technology, no directivity control is applied to the low-frequency component output from the woofers and thus the low-frequency component is located in front of the listener. As a result, the listener cannot feel the surround-sound feeling from the low-frequency component.
Meanwhile, as the typical sound in the low-frequency band and the medium low-frequency band, the low-pitched musical instrument such as a bass drum, a base, or the like and the fundamental of a human voice are cited. Respective sound sources are often aligned such that these sound are located in a center in producing the contents. At this time, even though the contents having the center channel are provided, there is such a tendency that, in view the fact that two-channel production and reproduction are the mainstream in the prior art, the same signals are still allocated to the left and right front channels (the so-called main channels). It is clearly intended that these sounds in the low-frequency band should be located in the center.
Therefore, even when either the array speaker unit whose low-frequency reproducing performance is high is provided or the array speaker for the low-frequency band only is employed, the problem still existed in producing the surround-sound feeling on the low-frequency band. In other words, when the same signals allocated to the left and right front channels are separately controlled, either the location and the articulation are deteriorated markedly or a sound pressure is attenuated on account of the superposition of the left and right channels whose phases are different and a loss of the low-pitched sound feeling occurs.